Estimation of Ecosystem Services improvement in the implementation of deep managed aquifer recharge in Llobregat delta (Spain)

The recurrent problems in water quality and water scarcity around Europe and more specifically in Mediterranean areas, require the implementation of innovative solutions and related methodologies to assess their impacts in terms of resource improvements and society benefits. The European water research project DESSIN developed a methodology for the evaluation of ecosystem services (ESS) changes associated with the implementation of innovative technological water solutions. The methodology was tested in three urban demo sites across Europe with a specific focus on freshwater ecosystems. The ESS framework builds upon existing classification systems for ESS (CICES and FEGS-CS) and incorporates the DPSIR adaptive management scheme as its main structural element. This enables compatibility with other international initiatives on ESS assessments and establishes a direct link to the EU Water Framework Directive, respectively (Anzaldua et al., 2018). This methodological approach to estimate the ESS has been applied in two Managed Aquifer Recharge systems of the Llobregat Delta (Barcelona, Spain): the existing infiltration ponds and the planned deep managed aquifer recharge with prepotable water. In the first case, the study focused on the economic valuation of changes in ESS provision using existing impact data. In the case of deep aquifer recharge the data of changes in ESS have been obtained from column studies and numerical models of groundwater flow. Additionally, information from surveys to local population has been included in the analysis. The evaluation of ESS changes that the implementation of the deep recharge would bring have included the quantification of drivers and pressures using specific indicators. The main changes are observed in the groundwater quality and quantity (decrease of contaminants and increase of potentiometric levels) but the analysis also reveals the importance of the increased groundwater storage which gives to the water managers more security for water supply to the population. The costs of the technology are lower than the saving costs estimated using the ESS approach. Main savings are related with less energetic costs for pumping and treating the water. But the most relevant saving is the fact that groundwater storage can offer an additional water resource for drought periods. Cultural services are also estimated and monetized. New cultural services, as research opportunities or education, are estimated together with improved cultural services (as landscape) to estimate the economic impact. As a result, in total, it is estimated that the implementation of the deep aquifer recharge would bring savings higher than 4.3 million €/year.